Precious and Semiprecious Stone Cut

ABSTRACT

The present invention provides a cut stone including a top surface and a bottom surface and a girdle. The top surface includes a first facet row having 18 facets, a second facet row having 6 facets, and a third facet row having 6 facets. The bottom surface includes a first facet row having 18 facets, a second facet row having 6 facets, and a third facet row having 6 facets. The girdle is disposed between the first facet row of the top surface and the first facet row of the bottom surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 60/672,528, filed Apr. 19, 2005, which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to precious and semiprecious stones, and, more particularly, to a new and unique gemstone cut.

2. Description of Related Art

The origins of gem cutting, or lapidary, date back to antiquity. Early artisans mastered sawing, chipping, drilling, polishing and even faceting, in materials such as jade, quartz, amber and turquoise. These craftsmen eventually progressed to ruby, sapphire, emerald, garnet and finally diamond, the hardest of gems. While a method of diamond cutting was practiced as early as the fourteenth century in France and developed gradually over the next several hundred years, the modern age of the round, brilliant cut diamond arrived with the publication of Marcel Tolkowsky's “Diamond Design” in 1919 describing the “ideal” proportions for cutting a diamond. Importantly, Tolkowsky's ideal diamond configuration has a well-defined front (i.e., the crown) and back (i.e., the pavilion). Today, variations on Tolkowsky's ideal dimensions include a slightly larger crown table and longer pavilion girdles.

As lapidaries began to apply these new diamond cutting techniques to other precious and semiprecious gemstones, color enhancement, promotion, dramatization, etc., became the predominant goal. Many different cuts have been developed, including stepped designs. However, none provide increased brightness and different brilliant colors to the cut gemstone.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the present invention provide a cut gemstone including a top surface and a bottom surface and a girdle. The top surface includes a first facet row having 18 facets, a second facet row having 6 facets, and a third facet row having 6 facets. The bottom surface includes a first facet row having 18 facets, a second facet row having 6 facets, and a third facet row having 6 facets. The girdle is disposed between the first facet row of the top surface and the first facet row of the bottom surface.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

The above and other advantages of this invention will become more apparent by the following description of invention and the accompanying drawings.

FIGS. 1A and 1B depict top and side views of a cut gemstone, according to an embodiment of the present invention.

FIG. 2 depicts top and side views of a cut gemstone, according to another embodiment of the present invention.

FIG. 3 depicts top views of cut gemstones mounted in various settings, according to embodiments of the present invention.

FIG. 4 depicts front and side views of cut gemstones mounted in a ring, according to an embodiment of the present invention.

FIG. 5 depicts top and section views of cut gemstones mounted in a necklace, according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1A and 1B depict top and side views of a cut gemstone, according to an embodiment of the present invention. Any of the well-known methods for cutting precious stones, semiprecious stones and cubic zirconium may be used to form the cut gemstone of the present invention. Advantageously, many different shapes may be cut, including, for example, round, pear, cushion, marquise, oval, etc.

As depicted in FIG. 1A, gemstone 100 includes a top surface 102 and a bottom surface 104. The top surface 102 includes three facet rows, a first facet row 110, a second facet row 130 and a third facet row 140. In a preferred embodiment, the first facet row 110 includes 18 individual facets, labeled 111 to 128, the second facet row 130 includes 6 facets, labeled 131 to 135, and the third facet row 140 includes 6 facets, labeled 141 to 145. Similarly, the bottom surface 104 includes three facet rows, a first facet row 150, a second facet row 170 and a third facet row 180. The first facet row 150 includes 18 individual facets, the second facet row 170 includes 6 facets and the third facet row 180 includes 6 facets. Thus, in the preferred embodiment, the top surface 102 includes 30 facets and the bottom surface 104 includes 30 facets, for a total of 60 facets. Other embodiments may include multiples of these facet counts. In contrast to other stone cuts, the faceting on the top surface 102 and the bottom surface 104 advantageously generates sparkle on the top and bottom surfaces 102, 104 of gemstone 100.

A girdle 106 is disposed between the first facet row 110 of the top surface 102 and the first facet row 150 of the bottom surface 104. The girdle 106 is dimensioned to advantageously increase the brilliance of the gemstone 100. In one embodiment, the girdle 106 is less than 0.6%, generally, while in other embodiments, the girdle may be thin, very thin, extremely thin, etc.

Generally, the top surface 102 and the bottom surface 104 are dome shaped, and neither the top surface 102, nor the bottom surface 104, includes a table. In the preferred embodiment, the top surface 102 and the bottom surface 104 are mirror images of each other. Again, in contrast to other diamond cuts which include a preferred orientation, the symmetric, two-sided cut of the present invention advantageously eliminates a back surface, allowing the gemstone 100 to be seen from many angles.

The various embodiments of the present invention may be incorporated into several different types of jewelry, such as, for example, earrings, necklaces, bracelets, etc., as depicted in FIG. 3. For example, gemstone 100 may be mounted within earring 300 using a prong setting 304. The earring 300 may include a post (not shown) for pierced ears, a clip, etc. Necklace 310 mounts gemstone 100 within a bezel setting 314 depending from a chain 312. Bracelet 320 mounts several gemstones 100 in a bar setting 324, while bracelet 330 mounts several gemstones 100 in a channel mount 334. Gemstone 100 may be generally mounted vertically within a ring 400, as depicted within FIG. 4. Either one ring body 404 or two ring bodies 404, 406 may be used.

One or more floating settings 504 may be used to mount gemstones 100 within a necklace 500, as stylistically depicted within the top view of FIG. 5. The floating settings 504 may be linked together using chain portions 502, while another chain portion 503, of the same or similar material, may complete the necklace. In other embodiments, chain portion 503 may be constructed of a different material, chain portion 503 may be a solid wire, chain portion 503 may include a clasp, etc. Section view A-A illustrates the various elements of the floating setting 504. A frame 505 encircles the gemstone 100, and, in a preferred embodiment, eight prongs, arranged as four prong pairs, secure the gemstone 100 to the frame 505. The prongs may be evenly distributed around the frame 505, as depicted within FIG. 5, or, alternatively, the prongs may be asymmetrically arranged. Two of the four prong pairs are visible within section view A-A, i.e., prongs 506 and 507, forming a first prong pair, and prongs 508 and 509, forming a second prong pair. Other embodiments include various arrangements of prong pairs, such as, for example, two prong pairs, three prong pairs, five prong pairs, etc. The floating setting 504 may also used to generally mount the gemstone 100 as a pendent for an earring, a bracelet, etc.

In one embodiment, the gemstone 100 has a depth of about 46%, as depicted in FIG. 1B. The first row of facets 110, 150 forms an angle with respect to the horizontal of about 50°, the second row of facets 130, 170 forms an angle with respect to the horizontal of about 15° and the third row of facets 140, 180 forms an angle with respect to the horizontal of about 10°. In other embodiments, the angle of the third row of facets 140, 180 may vary between 5° and 15°, which slightly alters the depth of the gemstone 100, assuming that the diameter and the other facet angles remain the same. However, the angle of the third row of facets 140, 180 does not approach 0°, thereby preventing the formation of a table on either the top surface 102 or the bottom surface 104.

Generally, the angle formed by the second row of facets 130, 170 is less than the angle formed by the first row of facets 110, 150, and the angle formed by the third row of facets 140, 180 is less than the angle formed by the second row of facets 130, 170. For illustration purposes, in FIGS. 1B and 2, the first row of facets 110 are labeled F₁ to F₁₈, the second row of facets 130 are labeled F₂₁ to F₂₆ and the third row of facets 140 are labeled F₃₁ to F₃₆.

In the embodiment depicted within FIG. 2, the gemstone 200 has a depth of 46% but different facet angles than gemstone 100. In this embodiment, the first row of facets forms an angle with respect to the horizontal of about 38°, the second row of facets forms an angle with respect to the horizontal of about 25° and the third row of facets forms an angle with respect to the horizontal of about 15°. In other embodiments, the angle of the third row of facets may vary between 5° and 25°, which slightly alters the depth of the gemstone 200, assuming that the diameter and the other facet angles remain the same. However, the angle of the third row of facets does not approach 0°, thereby preventing the formation of a table on either the top surface 102 or the bottom surface 104. Accordingly, the gemstones 100, 200 may have a depth of between about 36% to 56%.

While this invention has been described in conjunction with specific embodiments thereof, many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiments of the invention as set forth herein, are intended to be illustrative, not limiting. Various changes may be made without departing from the true spirit and full scope of the invention as set forth herein. 

1. A cut gemstone, comprising: a top surface, including: a first facet row having 18 facets, a second facet row having 6 facets, and a third facet row having 6 facets; a bottom surface, including: a first facet row having 18 facets, a second facet row having 6 facets, and a third facet row having 6 facets; and a girdle disposed between the first facet row of the top surface and the first facet row of the bottom surface.
 2. The cut gemstone of claim 1, wherein the gemstone consists of 60 facets.
 3. The cut gemstone of claim 2, wherein the gemstone has a depth of about 46%.
 4. The cut gemstone of claim 3, wherein the first facet row forms an angle with respect to the horizontal of about 50°.
 5. The cut gemstone of claim 4, wherein the second facet row forms an angle with respect to the horizontal of about 15°.
 6. The cut gemstone of claim 5, wherein the third facet row forms an angle with respect to the horizontal between about 10°.
 7. The cut gemstone of claim 2, wherein the second facet row forms an angle with respect to the horizontal that is less than an angle formed by the first facet row, and the third facet row forms an angle with respect to the horizontal that is less than the angle formed by the second facet row.
 8. The cut gemstone of claim 7, wherein the gemstone has a depth of about 36% to 56%, the first facet row forms an angle with respect to the horizontal of about 38° to 50°, the second facet row forms an angle with respect to the horizontal of about 15° to 25°, and the third facet row forms an angle with respect to the horizontal of between about 5° to 25°.
 9. The cut gemstone of claim 1, wherein the top and bottom surfaces are dome-shaped, mirror images.
 10. The cut gemstone of claim 1, wherein the stone is selected from a group consisting of a precious stone, a semiprecious stone and a cubic zirconium.
 11. The cut gemstone of claim 1, wherein a shape of the stone is selected from the group consisting of round, pear, cushion, marquise and oval.
 12. The cut gemstone of claim 1, wherein the girdle is thin, very thin or extremely thin.
 13. The cut gemstone of claim 1, wherein the girdle is less than 0.6%.
 14. A jewelry piece comprising a cut gemstone mounted in a setting, the cut gemstone including: a top surface having a first facet row having 18 facets, a second facet row having 6 facets, and a third facet row having 6 facets; a bottom surface having a first facet row having 18 facets, a second facet row having 6 facets, and a third facet row having 6 facets; and a girdle disposed between the first facet row of the top surface and the first facet row of the bottom surface.
 15. The jewelry piece of claim 14, wherein: the gemstone consists of 60 facets, the gemstone has a depth of between about 36% to 56%, the first facet row forms an angle with respect to the horizontal of between 38° to 50°, the second facet row forms an angle with respect to the horizontal smaller than the first facet row and between 15° to 25°, and the third facet row forms an angle with respect to the horizontal smaller than the second facet row and between 5° to 25°.
 16. The jewelry piece of claim 15, wherein the setting includes a frame encircling the gemstone and at least two pairs of prongs.
 17. The jewelry piece of claim 15, wherein the setting is a prong setting, a bezel setting, a bar setting or a channel setting.
 18. The jewelry piece of claim 15, wherein the gemstone and the setting are incorporated into an earring, a necklace, a bracelet or a ring.
 19. A cut gemstone, comprising: a top surface, including: a first facet row having a primary number of facets, a second facet row having a secondary number of facets less than the primary number of facets, and a third facet row having the secondary number of facets; a bottom surface, including: a first facet row having the primary number of facets, a second facet row having the secondary number of facets, and a third facet row having the secondary number of facets; and a girdle disposed between the first facet row of the top surface and the first facet row of the bottom surface.
 20. The cut gemstone of claim 19, wherein the primary number is three times larger than the secondary number.
 21. The cut gemstone of claim 20, wherein the primary number is a multiple of 18 and the secondary number is a multiple of
 6. 22. A jewelry piece comprising the cut gemstone recited in claim
 19. 